221331604 has 24 divisors (see below), whose sum is σ = 425000520. Its totient is φ = 100224384.

The previous prime is 221331563. The next prime is 221331611. The reversal of 221331604 is 406133122.

It can be written as a sum of positive squares in 4 ways, for example, as 52591504 + 168740100 = 7252^2 + 12990^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 37399 + ... + 42910.

It is an arithmetic number, because the mean of its divisors is an integer number (17708355).

Almost surely, 2^221331604 is an apocalyptic number.

It is an amenable number.

221331604 is a deficient number, since it is larger than the sum of its proper divisors (203668916).

221331604 is a wasteful number, since it uses less digits than its factorization.

221331604 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80379 (or 80377 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 22.

The square root of 221331604 is about 14877.2176162077. The cubic root of 221331604 is about 604.8966005019.

Adding to 221331604 its reverse (406133122), we get a palindrome (627464726).

The spelling of 221331604 in words is "two hundred twenty-one million, three hundred thirty-one thousand, six hundred four".